The invention relates to a security element and a security document with a security element.
It is known to equip banknotes with watermarks or security threads. These security elements provide a security feature which is recognizable in transmitted light. For inspection of these security features, the banknote is arranged between a light source, for example an artificial light source such as a neon tube or an incandescent light bulb or a natural light source such as for example the sun, and the observer and the appearance of the banknote is inspected in such a transmitted light observation. With this manner of observation, the light transmitted through the banknote is weakened differently in different areas of the banknote by the change in the transmissivity of the security document in the area covered with the watermark or security thread, with the result that a corresponding contrast becomes recognizable to the human observer as a security feature.